Developing on a mobile device isn't as practical and the final program has to have very specific dependencies in order to be 100% compatible. It's recommended that you develop your novel on a computer that allows you to even edit the Python code, to change things like the user interface or the player menus, for example. The other drawback for porting the editor to mobile is reliable dynamic screen formatting. If you're writing for mobile, both iOS and Android, then you have to make sure the interface is resizable to portrait, landscape, mobile device (phone), tablet (iPad, Samsung Tab, etc.) and laptops. The laptops are going to be a real challenge. With Chromebooks and the new Apple "SafariBook" coming out later this year to compete with Google compiling something complex that relies on the operating systems core system files is crazy hard. So, all that said, if you're serious about developing VNs and want to do it right, you'll want to find yourself a decent desktop or laptop computer (don't be proud, try Goodwill or your local technology recycling locations) and THEN, when you're ready, you compile the final code for your product (novel, game, etc.) from Ren'Py to mobile devices.